IEEE 802.15 wireless personal area network (WPAN) radios (sometimes referred to as Bluetooth® radios) provide low cost, low power, short range, ad-hoc connectivity among devices such as mobile phones, computers, and headsets. Bluetooth® technology uses frequency hopping spread spectrum technology and divides the 2.4 GHz Industrial, Scientific, and Medical (ISM) band into 791 MHz channels. The hop rate is 1600 hops per second, and time is divided into 625 microsecond slots. The basic Bluetooth® topology has a piconet with one master and up to seven slaves synchronized to the master's clock. Communications occurs only between a master and its slave. Time division duplexing is used for bi-directional communication, and a slave may transmit only when explicitly polled by its master.
Bluetooth® radios are often collocated with other wireless radios such as WiMAX, WiFi, UMTS, or LTE radios. In other words, Bluetooth® radios are often in a device with another radio. Examples include: a mobile phone with a UMTS radio and a Bluetooth® radio; and a laptop computer with a WiFi radio and a Bluetooth® radio. Additionally, Bluetooth® radios often operate in the vicinity of non-collocated radios such as other Bluetooth® radios and/or WiMAX, WiFi, UMTS, or LTE radios. Because these multiple radios can wirelessly interfere with each other, coexistence mechanisms should be developed for a variety of collocated and non-collocated scenarios.
Coexistence refers to the ability for multiple wireless protocols to operate in or around the same frequency band without significant degradation to any radio's operation. Without coexistence mechanisms, radio frequency interference can cause decreased data throughput and increased current drain.
In the ISM band at 2.4-2.5 GHz, Bluetooth® radios suffer and cause interference with other radios operating in the 2.4 GHz frequency band, such as other WPAN/Bluetooth® radios and IEEE 802.11b/g wireless local area network (WLAN) radios (sometimes referred to as WiFi radios). Next, Bluetooth® radios may also interfere with radios operating in the lower-adjacent Wireless Communication Service (WCS) band at 2.30-2.39 GHz, such as IEEE 802.16e wireless metropolitan area network (WMAN) radios (sometimes referred to as WiMAX or WiBro radios). Finally, Bluetooth radios can interfere with radios operating in the upper-adjacent Instructional Fixed Television Service (IFTS) and Multichannel Multipoint Distribution Services (MMDS) bands at 2.5-2.69 GHz frequency bands, which could be WiMAX radios or possibly LTE or WCDMA wireless wide area network (WWAN) radios.
With the continuing emergence of a variety of wireless communication technologies operating in frequencies overlapping or adjacent to the ISM frequency band, there is an opportunity to provide more effective solutions to mitigate interference and coexistence problems among collocated and non-collocated radios. The various aspects, features and advantages of the disclosure will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Drawings and accompanying Detailed Description.